The discussion centers around the theoretical derivation of the Lennard-Jones potential, specifically the components of the potential and their physical interpretations. Participants explore various sources, including papers and textbooks, that address the derivation and implications of the potential in the context of intermolecular forces.
Participants express differing views on the physical significance of the ##\frac{1}{r^{12}}## term, with some arguing it is merely a numerical artifact while others focus on the derivation of the ##\frac{1}{r^6}## term. The discussion remains unresolved regarding the interpretation of these components.
There are references to various sources that may contain derivations, but no consensus on a singular authoritative derivation is reached. The discussion includes assumptions about the physical relevance of certain terms in the potential.
A derivation can also be found in the 3-volume QM textbook by Cohen-Tannoudji, Diu and Laloe, Chapter XI.C.TeethWhitener said:The ##\frac{1}{r^6}## portion comes from treating the dipole-dipole interaction perturbatively to second order. This is actually the short-distance limit of the full interaction, not taking into account retardation effects. The full derivation in all its gory details of both short (London) and long (Casimir-Polder) limits is given in "Molecular Quantum Electrodynamics" by Craig and Thirunamachandran (p. 152ff): https://www.google.com/books/editio...rpbdozIZt3sC?hl=en&gbpv=1&printsec=frontcover